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C Computes AINV(NEL,3,3) which is the inverse of MAT(NEL,3,3)
Chd|====================================================================
Chd|  KMATINV3                      source/materials/tools/kmatinv.F
Chd|-- called by -----------
Chd|        CALCMATB                      source/materials/mat/mat100/calcmatb.F
Chd|        SIGEPS100                     source/materials/mat/mat100/sigeps100.F
Chd|        SIGEPS95                      source/materials/mat/mat095/sigeps95.F
Chd|-- calls ---------------
Chd|====================================================================
       SUBROUTINE KMATINV3(MAT, AINV  ,NEL)
C-----------------------------------------------
C   I m p l i c i t   T y p e s
C-----------------------------------------------
#include      "implicit_f.inc"
C-----------------------------------------------

      INTEGER I,NEL,N
C-----------------------------------------------

      my_real  FAC,DETA, MAT(NEL,3,3),AINV(NEL,3,3)
C-----------------------------------------------
C
        DO I= 1,NEL
          DETA=MAT(I,1,1)*MAT(I,2,2)*MAT(I,3,3) -MAT(I,1,1)*MAT(I,2,3)*MAT(I,3,2) -
     .         MAT(I,3,3)*MAT(I,1,2)*MAT(I,2,1) +MAT(I,1,2)*MAT(I,2,3)*MAT(I,3,1) +
     .         MAT(I,2,1)*MAT(I,3,2)*MAT(I,1,3) -MAT(I,2,2)*MAT(I,3,1)*MAT(I,1,3)
          IF(DETA == ZERO)DETA = EM20
          FAC=ONE/ DETA
          !transpose(comatrice)/det
          AINV(I,1,1)=FAC*(MAT(I,2,2)*MAT(I,3,3)-MAT(I,2,3)*MAT(I,3,2))
          AINV(I,2,2)=FAC*(MAT(I,1,1)*MAT(I,3,3)-MAT(I,3,1)*MAT(I,1,3))
          AINV(I,3,3)=FAC*(MAT(I,1,1)*MAT(I,2,2)-MAT(I,1,2)*MAT(I,2,1))
          AINV(I,1,2)=FAC*(MAT(I,3,2)*MAT(I,1,3)-MAT(I,3,3)*MAT(I,1,2))
          AINV(I,2,3)=FAC*(MAT(I,2,1)*MAT(I,1,3)-MAT(I,1,1)*MAT(I,2,3))
          AINV(I,3,1)=FAC*(MAT(I,2,1)*MAT(I,3,2)-MAT(I,2,2)*MAT(I,3,1))
          AINV(I,2,1)=FAC*(MAT(I,2,3)*MAT(I,3,1)-MAT(I,3,3)*MAT(I,2,1))
          AINV(I,3,2)=FAC*(MAT(I,1,2)*MAT(I,3,1)-MAT(I,1,1)*MAT(I,3,2))
          AINV(I,1,3)=FAC*(MAT(I,1,2)*MAT(I,2,3)-MAT(I,2,2)*MAT(I,1,3))
        
        ENDDO  
C
      RETURN
      END      
